32,576 results match your criteria mass spectra

Counter-directed leucine gradient promotes amino acid transfer across the human placenta.

J Nutr Biochem 2021 May 5:108760. Epub 2021 May 5.

Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Switzerland; Swiss National Centre of Competence in Research (NCCR) TransCure, University of Bern, Switzerland. Electronic address:

The developing fetus is highly vulnerable to imbalances in the supply of essential amino acids (AA). Transplacental AA transfer depends on complex interactions between accumulative transporters, exchangers and facilitators, which maintain both intra-extracellular and materno-fetal substrate gradients. We determined physiological AA gradients between maternal and fetal blood and assessed their importance by studying maternal-fetal leucine transfer in human trophoblasts. Read More

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Unraveling the mechanism of efficient adsorption of riboflavin onto activated biochar derived from algal blooms.

J Environ Manage 2021 May 5;291:112725. Epub 2021 May 5.

School of Geographic Sciences, Nantong University, Nantong, 226007, China. Electronic address:

Riboflavin is commercially produced primarily by bio-fermentation. Nonetheless, purification and separation are particularly complex and costly. Adsorption from the fermentation liquor is an alternative riboflavin separation technology during which a cost-efficient adsorbent is highly desired. Read More

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Insights into the sodiation mechanism of hard carbon-like materials from electrochemical impedance spectroscopy.

Phys Chem Chem Phys 2021 May 7. Epub 2021 May 7.

Department of Colloid Chemistry, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany.

To render the sodium ion battery (SIB) competitive among other technologies, the processes behind sodium storage in hard carbon anodes must be understood. For this purpose, electrochemical impedance spectroscopy (EIS) is usually undervalued, since fitting the spectra with equivalent circuit models requires an a priori knowledge about the system at hand. The analysis of the distribution of relaxation times (DRT) is an alternative, which refrains from fitting arbitrarily nested equivalent circuits. Read More

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Current and future deep learning algorithms for MS/MS-based small molecule structure elucidation.

Rapid Commun Mass Spectrom 2021 May 6:e9120. Epub 2021 May 6.

Janssen Research & Development, Beerse, Belgium.

Rationale: Structure elucidation of small molecules has been one of the cornerstone applications of mass spectrometry for decades. Despite the increasing availability of software tools, structure elucidation from MS/MS data remains a challenging task, leaving many spectra unidentified. However, as an increasing number of reference MS/MS spectra are being curated at a repository scale and shared on public servers, there is an exciting opportunity to develop powerful new deep learning (DL) models for automated structure elucidation. Read More

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MALDI-MS Profiling of Intact Blood Proteins without the Need for Freezing - Dried Serum Spots as Future Clinical Tools for Patient Screening.

Rapid Commun Mass Spectrom 2021 May 5:e9121. Epub 2021 May 5.

Proteome Center Rostock, Medical Faculty and Natural Science Faculty, University of Rostock, Schillingallee 69, 18057, Rostock, Germany.

Rationale: To open new ways for MALDI-MS-based patient screening, blood serum is the most preferred specimen because of its richness in patho-physiological information and due to ease of collection. To overcome deleterious freeze/thaw cycles and to reduce high costs for shipping and storage, we sought to develop a procedure which enables MALDI-MS protein profiling of blood serum proteins without the need for serum freezing.

Methods: Blood sera from patients/donors were divided into portions which after pre-incubation were fast frozen. Read More

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Mass Spectrometry-Based Shotgun Lipidomics Using Charge-Switch Derivatization for Analysis of Complex Long-Chain Fatty Acids.

Methods Mol Biol 2021 ;2306:93-103

Mass Spectrometry Resource, Division of Endocrinology, Metabolism, and Lipid Research, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA.

Charge-switch derivatization to convert long-chain fatty acids (LCFAs) to their N-(4-aminomethylphenyl) pyridinium (AMPP) derivatives (FA-AMPP derivative) drastically increases their sensitivity (>10) detected by electrospray ionization (ESI) or matrix assisted laser desorption ionization (MALDI). Lipidomic analyses of the FA-AMPP derivatives by ESI combined with CID tandem mass spectrometry (MS), or by MALDI-TOF/TOF affords unambiguous structural characterization of LCFAs, including many unusual microbial LCFAs that contain various functional groups such as methyl, hydroxyl, cyclopropyl, and double bond(s). The ease of preparation of the FA-AMPP derivatives, the tremendous gain in sensitivity after derivatization, and more importantly, the readily recognizable product ion spectra that contain rich structurally informative fragment ions for locating functional groups make this method one of the most powerful techniques for LCFA identification and quantification. Read More

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January 2021

Global Lipidomics Profiling by a High Resolution LC-MS Platform.

Methods Mol Biol 2021 ;2306:39-51

Core Facility Mass Spectrometry, Medical University of Graz, Graz, Austria.

Lipidomics is the determination of big lipid assemblies by mass spectrometry. When using chromatography coupled high resolution mass spectrometry, lipids can be identified by exact mass, fragment spectra, and retention time. This protocol covers lipid extraction, LC-MS data acquisition by Orbitrap mass spectrometry and data processing by Lipid Data Analyzer, a custom developed open source software. Read More

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January 2021

Investigation of electrical properties of eco-friendly vegetable oil blended with bioactive compound.

Environ Sci Pollut Res Int 2021 May 6. Epub 2021 May 6.

Department of Electrical and Electronics Engineering, SASTRA Deemed University, Thanjavur, 613 401, India.

Oxidative stability of prototypical groundnut oil (GO) and mustard oil (MO) blended with a significant characteristic addition of antioxidants, α-tocopherol (α-T) and TBHQ (tert-butyl hydroquinone), at different concentrations was analysed. α-T (natural) and TBHQ (synthetic) antioxidants at a different concentrations from 0 to 20 mg/L were blended with GO and MO to prepare 18 samples. Compositional analysis of groundnut oil and mustard oil was carried out using gas chromatography and mass spectra (GCMS). Read More

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Targeted Protein Quantification Using Parallel Reaction Monitoring (PRM).

Methods Mol Biol 2021 ;2228:145-157

Medizinisches Proteom-Center (MPC), Ruhr-Universität Bochum, Bochum, Germany.

Targeted proteomics represents an efficient method to quantify proteins of interest with high sensitivity and accuracy. Targeted approaches were first established for triple quadrupole instruments, but the emergence of hybrid instruments allowing for high-resolution and accurate-mass measurements of MS/MS fragment ions enabled the development of parallel reaction monitoring (PRM). In PRM analysis, specific peptides are measured as representatives of proteins in complex samples, with the full product ion spectra being acquired, allowing for identification and quantification of the peptides. Read More

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January 2021

An Approach for Triplex-IPTL.

Methods Mol Biol 2021 ;2228:133-144

Department of Biosciences, University of Oslo, Oslo, Norway.

Isobaric peptide termini labeling (IPTL) is an approach for quantitative proteomics based on crosswise isotopic labeling of peptides at the N- and C-terminus. The labeling reagents are chosen in isotopic variations that the resulting mass of all labels per peptide is isobaric, but the individual label on each peptide terminus is different. Therefore, the quantitative difference of the peptide signal can be determined by the fragment ions of the corresponding MS2 spectra. Read More

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January 2021

Ionisation of PF: absolute partial electron ionisation cross sections and the formation and reactivity of dication states.

Phys Chem Chem Phys 2021 May 5. Epub 2021 May 5.

Department of Chemistry, University College London, London WC1H 0AJ, UK.

Absolute partial electron ionisation cross sections, and precursor-specific partial electron ionisation cross sections, for the formation of cations from phosphorus trifluoride (PF3) are reported over the electron energy range 50-200 eV. The absolute values are determined by the measurement of cross sections relative to the formation of PF3+ using 2D ion-ion coincidence time-of-flight mass spectrometry and subsequent scaling using binary encounter-Bethe calculations of the total ionisation cross section. This new dataset significantly augments the partial ionisation cross sections for electron ionization of PF3 found in literature, addressing previous discrepancies in the branching ratios of product ions, and provides the first values for the precursor-specific cross sections. Read More

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Comparison of Targeted and Untargeted Approaches in Breath Analysis for the Discrimination of Lung Cancer from Benign Pulmonary Diseases and Healthy Persons.

Molecules 2021 Apr 29;26(9). Epub 2021 Apr 29.

Department of Hygiene and Epidemiology, University Hospital of Larissa, Faculty of Medicine, University of Thessaly, 22 Papakyriazi Street, 41222 Larissa, Greece.

The aim of the present study was to compare the efficiency of targeted and untargeted breath analysis in the discrimination of lung cancer (Ca+) patients from healthy people (HC) and patients with benign pulmonary diseases (Ca-). Exhaled breath samples from 49 Ca+ patients, 36 Ca- patients and 52 healthy controls (HC) were analyzed by an SPME-GC-MS method. Untargeted treatment of the acquired data was performed with the use of the web-based platform XCMS Online combined with manual reprocessing of raw chromatographic data. Read More

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SWATH Based Quantitative Proteomics Reveals Significant Lipid Metabolism in Early Myopic Guinea Pig Retina.

Int J Mol Sci 2021 Apr 29;22(9). Epub 2021 Apr 29.

Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China.

Most of the previous myopic animal studies employed a single-candidate approach and lower resolution proteomics approaches that were difficult to detect minor changes, and generated limited systems-wide biological information. Hence, a complete picture of molecular events in the retina involving myopic development is lacking. Here, to investigate comprehensive retinal protein alternations and underlying molecular events in the early myopic stage, we performed a data-independent Sequential Window Acquisition of all Theoretical Mass Spectra (SWATH) based proteomic analysis coupled with different bioinformatics tools in pigmented guinea pigs after 4-day lens-induced myopia (LIM). Read More

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Simultaneous Determination of As, Bi, Sb, Se, Te, Hg, Pb and Sn by Small-Sized Electrothermal Vaporization Capacitively Coupled Plasma Microtorch Optical Emission Spectrometry Using Direct Liquid Microsampling.

Molecules 2021 Apr 30;26(9). Epub 2021 Apr 30.

Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, Arany Janos 11, 400028 Cluj-Napoca, Romania.

The simultaneous determination of chemical vapor-generating elements involving derivatization is difficult even by inductively coupled plasma optical emission spectrometry or mass spectrometry. This study proposes a new direct liquid microsampling method for the simultaneous determination of As, Bi, Se, Te, Hg, Pb, and Sn, using a fully miniaturized set-up based on electrothermal vaporization capacitively coupled plasma microtorch optical emission spectrometry. The method is cost-effective, free from non-spectral interference, and easy to run by avoiding derivatization. Read More

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Chemical Constitution and Antimicrobial Activity of Kefir Fermented Beverage.

Molecules 2021 Apr 30;26(9). Epub 2021 Apr 30.

Department of Botany and Microbiology, Faculty of Science, Zagazig University, Zagazig 44519, Egypt.

Kefir beverage (KB) is a fermented milk initiated by kefir grains rich with starter probiotics. The KB produced in this study seemed to contain many chemical compounds elucidated by gas chromatography-mass spectrometry (GC-MS) and IR spectra. These compounds could be classified into different chemical groups such as alcohols, phenols, esters, fatty esters, unsaturated fatty esters, steroids, polyalkenes, heterocyclic compounds and aromatic aldehydes. Read More

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Hygroscopic behavior and chemical reactivity of aerosols generated from mixture solutions of low molecular weight dicarboxylic acids and NaCl.

Phys Chem Chem Phys 2021 May 4. Epub 2021 May 4.

Department of Chemistry, Inha University, Incheon 22212, Korea.

Ambient sea spray aerosols (SSAs) have been reported to undergo reactions with low molecular weight dicarboxylic acids (LMW DCAs). In the present study, the hygroscopic behavior of aerosols generated from NaCl-LMW DCA mixture solutions with different mixing ratios was explained. In situ Raman microspectrometry (RMS) was used to simultaneously monitor the alterations in chemical composition, size, and phase as a function of the relative humidity (RH) for individual aerosols. Read More

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LC-MS Behavior of Girard's Reagent T Derivatives of Oxosteroid Intact Phase II Metabolites for Doping Control Purposes.

Drug Test Anal 2021 May 3. Epub 2021 May 3.

Doping Control Laboratory of Athens, Institute of Biosciences & Applications, National Center for Scientific Research "Demokritos", Neratziotissis & Amaryssias Artemidos Str, 15123, Athens, Greece.

Intact phase II steroid metabolites have poor product ion mass spectra under collision induced dissociation (CID) conditions. Therefore, we present herein the liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/(MS)) behavior of intact phase II metabolites of oxosteroids after derivatization. Based on the fact that Girard's reagent T (GRT), as derivatization reagent, was both convenient and efficient in terms of the enhancement in the ionization efficiency and the production of diagnostic product ions related to the steroid moiety, the latter was preferably selected between methoxamine and hydroxylamine upon the model compounds of androsterone glucuronide and androsterone sulfate. Read More

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On the redox property of AgAu clusters: One-way conversion from anionic [AuAgL] to charge neutral [AuAgL].

J Chem Phys 2021 Apr;154(16):164308

State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.

The redox property of metal nanoclusters plays a pivotal role and is of particular interest in catalysis and other applications, such as aerobic oxidation, hydrogenation, and singlet oxygen generation, over intact nanoclusters. In this study, we report a one-way conversion process of the anionic [AgAuL] nanocluster into a charge neutral nanocluster of [AgAuL] via oxidation in a solution phase using HO as the oxidant. Three-electron loss of [AgAuL] occurred during the oxidation process, which was confirmed by electron paramagnetic resonance and electrospray ionization mass spectrometry methods. Read More

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Untargeted lipidomics analysis of Mori Fructus polysaccharide on acute alcoholic liver injury in mice using ultra performance liquid chromatography-quadrupole-orbitrap-high resolution mass spectrometry.

Int Immunopharmacol 2021 May 1;97:107521. Epub 2021 May 1.

Key Laboratory for Information System of Mountainous Areas and Protection of Ecological Environment, Guizhou Engineering Laboratory for Quality Control and Evaluation Technology of Medicine, Research Center for Quality Control of Natural Medicine, Guizhou Normal University, Guiyang 550001, China. Electronic address:

Ethnopharmacological Relevance: Mori Fructus (MF) is a traditional Chinese medicine with long application history, which has protective effects on liver diseases. Mori Fructus polysaccharide (MFP) is one of the active ingredients of MF and possesses therapeutic effects against acute alcoholic liver injury. Recent researches have reported that the therapeutic effects of MFP might be related to the regulation of several lipid metabolic pathways. Read More

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Strategy for the identification of flavor compounds in e-liquids by correlating the analysis of GCxIMS and GC-MS.

Talanta 2021 Aug 26;230:122318. Epub 2021 Mar 26.

Faculty of Chemistry, Instrumental Analytical Chemistry, University of Duisburg-Essen, Universitätsstrasse 5, 45141, Essen, Germany. Electronic address:

This work presents a strategy to correlate the results from gas chromatography coupled ion mobility spectrometry (GCxIMS) and mass spectrometry (GC-MS) to enable a simpler and cheaper analysis of flavor compounds in e-liquids. The use of the retention index for GCxIMS measurements was validated for its application to correlate results with GC-MS data. The easy detection of the GCxIMS for substances at concentrations as low as 1 μg/L can therefore be combined with the identification power of the MS. Read More

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A fast and effective approach for the discrimination of garlic origin using wooden-tip electrospray ionization mass spectrometry and multivariate classification.

Talanta 2021 Aug 26;230:122304. Epub 2021 Mar 26.

Department of Chemistry, Institute of Exact Sciences, Federal University of Minas Gerais, 31270-901, Belo Horizonte, MG, Brazil. Electronic address:

This paper presents the combination of wooden-tip electrospray ionization mass spectrometry (WTESI-MS) and multivariate pattern recognition methods (principal component analysis, PCA and partial least squares discriminant analysis, PLS-DA) for the rapid and reliable discrimination, via chemical fingerprints, of garlic origin. A total of 312 garlic samples grown in different countries (Brazil, China, Argentina, Spain, and Chile) were studied. The methodology was based on a direct sampling approach, which relies on loading the sample by penetrating the garlic cloves with a pre-wetted wooden tip, followed by direct prompt analysis by WTESI-MS. Read More

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Non-targeted screening of trace organic contaminants in surface waters by a multi-tool approach based on combinatorial analysis of tandem mass spectra and open access databases.

Talanta 2021 Aug 19;230:122293. Epub 2021 Mar 19.

Department of Chemistry, Université de Sherbrooke, Sherbrooke, QC, Canada. Electronic address:

Non-targeted screening (NTS) in mass spectrometry (MS) helps alleviate the shortcoming of targeted analysis such as missing the presence of concerning compounds that are not monitored and its lack of retrospective analysis to subsequently look for new contaminants. Most NTS workflows include high resolution tandem mass spectrometry (HRMS) and structure annotation with libraries which are still limited. However, in silico combinatorial fragmentation tools that simulate MS spectra are available to help close the gap of missing compounds in empirical libraries. Read More

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Solid-phase synthesis of D-fructose-derived Heyns peptides utilizing N-Fmoc-Lysin[N-(2-deoxy-D-glucos-2-yl),N-Boc]-OH as building block.

Amino Acids 2021 May 2. Epub 2021 May 2.

Institut Für Bioanalytische Chemie, Fakultät Für Chemie Und Mineralogie, Universität Leipzig, Leipzig, Germany.

Aldoses and ketoses can glycate proteins yielding isomeric Amadori and Heyns products, respectively. Evidently, D-fructose is more involved in glycoxidation than D-glucose favoring the formation of advanced glycation endproducts (AGEs). While Amadori products and glucation have been studied extensively, the in vivo effects of fructation are largely unknown. Read More

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Influence of rice husk addition on phosphorus fractions and heavy metals risk of biochar derived from sewage sludge.

Chemosphere 2021 Apr 26;280:130566. Epub 2021 Apr 26.

School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, China. Electronic address:

This study investigated the effects of rice husk dose and pyrolysis temperature on the phosphorus (P) fractions and environmental risk of heavy metals in biochar co-pyrolyzed from sewage sludge and rice husk. Biochar properties were analyzed, and the transformation of P and heavy metals speciation during co-pyrolysis were also discussed. Co-pyrolysis of raw sludge and rice husk (10-50 wt%) could increase the carbonization degree and stability of biochar at 500 °C. Read More

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Unique ion filter - A data reduction tool for chemometric analysis of raw comprehensive two-dimensional gas chromatography - mass spectrometry data.

J Sep Sci 2021 May 1. Epub 2021 May 1.

Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada.

Comprehensive GC with time of flight MS, is a powerful tool in the analysis of complex samples. Chemometric analysis of raw chromatographic data is more useful in one- and two-dimensional separations relative to peak tables. The data volume from such experiments generally necessitates the use of data reduction tools. Read More

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Four new polyacetylenes from the roots of .

Nat Prod Res 2021 Jan 10:1-8. Epub 2021 Jan 10.

Key Laboratory of Chinese Materia Medica (Ministry of Education), Heilongjiang University of Chinese Medicine, Harbin, P.R. China.

Four new polyacetylene substances, sadivaethynes A-D, were isolated from the ethanol extract of the roots of (Turcz.) Schischk using repeated column chromatography. Structural elucidation of compounds was established by 1D and 2D NMR spectra referring to the literature, together with high-resolution mass spectrometric analysis. Read More

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January 2021

Keggin-type polyoxometalate 1 : 1 complexes of Pb(II) and Bi(III): experimental, theoretical and luminescence studies.

Dalton Trans 2021 Apr 30. Epub 2021 Apr 30.

Nikolaev Institute of Inorganic Chemistry, 3 Akad. Lavrentiev Ave. 630090, Russia.

Bi3+ and Pb2+ uptake by a monolacunary Keggin-type [PW11O39]7- anion leads to the formation of [PW11O39Bi]4- and [PW11O39Pb]5- complexes with a stereochemically active lone pair at the incorporated heterometal. The two complexes were isolated as (TBA)4[PW11O39Bi] (1) and (TBA)5[PW11O39Pb] (2) and characterized by 31P and 183W NMR spectroscopy, high-resolution electrospray mass-spectrometry (HR-ESI-MS) and cyclic voltammetry (CV). EXAFS and XANES data confirm the unchanged oxidation state and ψ-square pyramidal geometry of Bi3+ and Pb2+ in 1 and 2. Read More

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Spectroscopic characterization of a thermodynamically stable doubly charged diatomic molecule: MgAr.

Phys Chem Chem Phys 2021 Apr 30. Epub 2021 Apr 30.

Laboratory of Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland.

Although numerous doubly positively charged diatomic molecules (diatomic dications) are known from investigations using mass spectrometry and ab initio quantum chemistry, only three of them, NO2+, N22+ and DCl2+, have been studied using rotationally resolved optical spectroscopy and only about a dozen by vibrationally resolved double-ionization methods. So far, no thermodynamically stable diatomic dication has been characterized spectroscopically, primarily because of experimental difficulties associated with their synthesis in sufficient densities in the gas phase. Indeed, such molecules typically involve, as constituents, rare-gas, halogen, chalcogen, and metal atoms. Read More

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Innovative Method for Coating of Natural Corrosion Inhibitor Based on .

Materials (Basel) 2021 Apr 26;14(9). Epub 2021 Apr 26.

Calculo Científico y Modelamiento Matemático, Universidad Nacional de Colombia sede Manizales, Manizales-Caldas 170003, Colombia.

In this work, the production of a novel methodology for the application of natural corrosion inhibitors on steel, using an autoclave is presented. Tests were carried out using . The inhibitor was produced with a simple soxhlet extraction process using 15 g of and 260 mL of Ether. Read More

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Synthesis, Biomacromolecular Interactions, Photodynamic NO Releasing and Cellular Imaging of Two [RuCl(qn)(Lbpy)(NO)]X Complexes.

Molecules 2021 Apr 27;26(9). Epub 2021 Apr 27.

Key Laboratory of Chemical Biology and Molecular Engineering of the Education Ministry, Institute of Molecular Science, Shanxi University, Taiyuan 030006, China.

Two light-activated NO donors [RuCl(qn)(Lbpy)(NO)]X with 8-hydroxyquinoline (qn) and 2,2'-bipyridine derivatives (Lbpy) as co-ligands were synthesized (Lbpy = 4,4'-dicarboxyl-2,2'-dipyridine, X = Cl and Lbpy = 4,4'-dimethoxycarbonyl-2,2'-dipyridine, X = NO), and characterized using ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (H NMR), elemental analysis and electrospray ionization mass spectrometry (ESI-MS) spectra. The [RuCl(qn)(Lbpy)(NO)]NO complex was crystallized and exhibited distorted octahedral geometry, in which the Ru-N(O) bond length was 1.752(6) Å and the Ru-N-O angle was 177. Read More

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